One of the things to test when test benching the performance of an audio/video receiver such as a set top box or digital television receiver, is the correct execution of a channel change under varying circumstances and for different channel sources and audio/video configurations. If many audio/video receivers are tested simultaneously, e.g., in a video-wall like set up for a test bed configuration, it is difficult for a single test engineer to verify audio rendering features individually for all the tested audio/video receivers, e.g. after a channel change. There is a difficulty, when confronted with a multitude of simultaneous audio sources, to identify which of the tested audio/video receiver produces which audio. An audio switch may help to enable a test operator to switch between identified audio sources for monitoring of channel change and to verify if and when audio is rendered with video, e.g., after a channel change. But manually testing many receivers is long and tedious. In addition, the test engineer may be induced in error when a channel change or a change of audio/video source is operated during a silence on the new channel or the changed audio/video source. This results in audio being rendered relatively late in the channel change or in the audio/video source change process, and the test engineer may erroneously conclude that the tested audio/video receiver does not function properly. Further, it may be difficult for the test engineer to verify (lip) synchronization between audio and video after a channel change when the audio channel that accompanies the video of the new channel cannot be directly and visibly related to movement in the video.
For viewers that watch videos such as proposed by the video-sharing website YouTube, it is interesting to know if a video comprises audio or not and at what volume level audio is set, since a significant number of videos are proposed without audio and audio volume levels are not standardized.
For a viewer of an audio/video stream rendered by an audio/video rendering device, it is difficult to verify the presence of audio in an audio/video stream in a noisy environment or when audio is muted. Headphones can cause serious hearing loss to its wearer when the user is unaware that the audio will be rendered at high volume when audio is unmuted.
There is thus a need for improvement of detection of audio associated with video.